Electrostatic sound generators



Jan. 17, 1967 M. M. IRASTORZA I 3,299,198

ELECTROSTAT IC SOUND GENERATORS Fil ed Nov. 5 1963 United States Patent Claims. (01. 84-1.28)

This invention relates to an electrostatic sound generator,

Sound generators are known which use electrostatic members having 12 generator sub-components corresponding to the 12 semi-tones of the musical chromatic scale.

Each generator sub-component comprises two oppositely disposed plates, A and B in FIG. 1, having on their inner face formations of sounds which are scanned and analysed by a rotor disc C which is located between, and generally equidistant from, the plates.

The sound generator of the present invention has the great advantage of reducing the number of 12 generator sub-components which have hitherto been necessary in this class of instrument, to seven only.

This has the advantage of involving less wear and tear, less mechanical noise, a saving of generator subcomponents, a saving of space, less motor power, less residual capacity with the consequent increase of the sound level in the high pitched notes and less speed of the movable components of the generator sub-components than in the previous sound generators having 12 subcomponents.

Furthermore, the sound generator occupies less space, is quieter from the electrical point of view, has a shorter transmission belt, is more easily assembled and the mechanical adjustment or alignment is readily effected and is much more economical than the previous sound generators having 12 sub-components.

Since the electrical noise generated by the movable contacts is less because the unit has fewer generator sub-components and these rotate with less velocity than previous generators, the contact usually employed hitherto in this class of instrument may be replaced by a brush of graphite, metalographitic or of metal of a type known per se thus enabling further convenience and economy.

In the sound generator according to the invention there may be seven sub-components, five of which carry in addition to the series of the forms which represent a note in a key or in different keys and to its different levels in an octave, a second series of the same characteristics but which are related by a fifth to the characteristics of the first series.

The invention will be further described with reference to the accompanying drawings in which:

FIG. 2 shows a sound generator having seven generator sub-components;

FIGS. 3, 4, 5 and 6 show the plates of the subcomponents.

The generator (FIG. 2) has seven generator subcomponents which may be distributed as follows:

Sub component No. l-C; sub-component No. 2-C sharp; sub-component No. 3-D; sub-component No. 4D sharp; sub-component No. S-E; sub-component No. 6-F; sub-component No. 7-F sharp.

If the relative dimensional distribution of the impulse poles of each generator sub-component is the same as that of the primary sub-components used in the generators which have 12 sub-components, there will be no impediment to the tones and their distribution will be correct as far as F sharp inclusive, the seventh note corresponding to the seventh sub-component. The next note, G, is obtained by using the fifth of C which is carried by subcomponent No. 1. Similarly successive notes are obtained 3,299,198 Patented Jan. 17, 1967 by using the fifths of C sharp, of D and D sharp and B, so as to complete the cycle of the musical chromatic scale.

By using this process having only 7 generator subcomponents, the 12 semi-tones of the musical scale in its various octaves are obtained.

In practice the Sths are not used unless it is desired to obtain them in the remaining sub-components, although there is no disadvantage in using them at certain points of the scale in order to obtain certain beats which could result in producing pleasant effects.

Although on principle by means of this system ther are very slight errors in the division of the musical scale obtained in this manner, they are below normal tolerances which are usually permitted in the mechanisation of the generator. Nevertheless, taking an extreme case, these errors can be compensated in the high octaves by slightly modifying the number of cycles represented in the forms of the second series.

FIGS. 3, 4, 5 and 6 show the forms of the plates of the sub-components with their corresponding analysers showing, for greater clarity, only one tone per octave.

In FIG. 3, D represents the forms of the first series of a note in its various octaves and with only one note in each octave. In FIG. 4, E represents the forms of the second series of a note in its various octaves which are related by a 5 th with the first.

In FIG. 5 F shows an analyser seen obverse and in FIG 6 G in reverse, in which analyser F scans and analyses D and G, scans and analyses G.

There is no disadvantage in this generator which has just been described in locating the two series of forms, musically related by Sths, on a single surface and reading them by analysers suitably designed for this purpose. Again, there are no disadvantages in using in this case if desired the other free plate, including therein another two series of different characteristics in note and in pitch, but always related musically by a 5th and having analysers capable of reading them.

The simplification obtained by this new generator enables it to be coupled with other generators of identical or similar characteristics to obtain stereophonic, emphasis and damping effects of the sounds with a level of interference of the order approximately that produced by generators using 12 sub-components.

The change of forms and sizes as also the arrangement of the components may vary provided that its essen tial characteristics are not changed.

I claim:

1. An electrostatic tone generator comprising at least one scanning electrode, a first tone pattern positioned adjacent said scanning electrode and having a reentrant tone pattern representative of a first selected note in the musical scale, a second tone pattern positioned adjacent said scanning electrode and having a reentrant tone pattern representative of a note in the musical scale having a pitch related by a musical fifth to said first note, and means for effecting rotary movement between said scanning electrode and said first and second tone patterns to cause said scanning electrode to generate signals representative of said selected note and said note bearing a musical fifth pitch relationship thereto, said first and second tone patterns having a stationary relationship to each other during said rotary movement.

2. An electrical musical instrument comprising a first plurality of the electrostatic tone generators as defined in claim 1, the pitch of each of said first tone patterns being related to each other in accordance with the musical intervals of the tempered scale, and including a second plurality of electrostatic tone generators comprising individual scanning electrodes and tone patterns each positioned adjacent a respective scanning electrode and each having a reentrant tone pattern representative of a selected note in the musical scale, and individual driving means for effecting rotary movement between each individual scanning electrode and each associated tone pattern of said second plurality, to cause said scanning electrodes to generate musical notes related to each other and to said first tone pattern in accordance with the musical intervals of the tempered scale.

3. The electrical musical instrument defined in claim 2, including at least five of said electrostatic tone generators of said first plurality.

4. The invention defined in claim 1 including a plurality of reentrant tone patterns octavely related to said first tone patterns.

5. The invention defined in claim 1, including a backing member for said tone patterns and wherein said first and second reentrant tone patterns are disposed on the same surface of said backing member.

References Cited by the Examiner UNITED STATES PATENTS 1,967,239 7/1934 Hardy 84-1.28 X 2,469,850 5/1949 Spielman 84l.l8 2,959,083 11/1960 Dereux 84-128 3,000,252 9/1961 Wayne 841.01 

1. AN ELECTROSTATIC TONE GENERATOR COMPRISING AT LEAST ONE SCANNING ELECTRODE, A FIRST TONE PATTERN POSITIONED ADJACENT SAID SCANNING ELECTRODE AND HAVING A REENTRANT TONE PATTERN REPRESENTATIVE OF A FIRST SELECTED NOTE IN THE MUSICAL SCALE, A SECOND TONE PATTERN POSITIONED ADJACENT SAID SCANNING ELECTRODE AND HAVING A REENTRANT TONE PATTERN REPRESENTATIVE OF A NOTE IN THE MUSICAL SCALE HAVING A PITCH RELATED BY A MUSICAL FIFTH TO SAID FIRST NOTE, AND MEANS FOR EFFECTING ROTARY MOVEMENT BETWEEN SAID SCANNING ELECTRODE AND SAID FIRST AND SECOND TONE PATTERNS TO CAUSE SAID SCANNING ELECTRODE TO GENERATE SIGNALS REPRESENTATIVE OF SAID SELECTED NOTE AND SAID NOTE BEARING A MUSICAL FIFTH PITCH RELATIONSHIP THERETO, SAID FIRST AND SECOND TONE PATTERNS HAVING A STATIONARY RELATIONSHIP TO EACH OTHER DURING SAID ROTARY MOVEMENT. 